In recent years, a network service such as a FTTH (Fiber To The Home), a NGN (Next Generation Network), or the like is provided. By using such a network service, a high speed and high quality network connection environment can be used in a home. Because a high speed and high quality network has been able to be used, an infrastructure which uses a distribution service of a video content that requires a high bit rate and a real time property has been improved. A content distribution service such as a VoD (Video on Demand) in which a user views a desired content among the contents provided by a provider is provided. Moreover, in some countries, a new video viewing service has started in which a user views a content in response to a user's selection of broadcast content or in response to a user's selection of content automatically recorded on a server. This new video viewing service is called a nDVR (network-based Digital Video Recorder).
When the video content is viewed via a network like a television broadcast, a video distribution server performs only a process in which a stream is transmitted to a player in order from the beginning of the content. However, a video service such as the VoD, the nDVR, or the like in which the stored content is distributed according to the user's request provides a trick play function such as fast-forwarding, rewinding, and halt. In particular, in the nDVR in which the broadcast content is automatically recorded, the user frequently uses the fast-forwarding or the like to find out a scene that the user wants to view from the recorded result. Consequently, the trick play function has become important than ever before.
An example of a method of fast forwarding a stored content is described in patent document 1. In this method, a read-out process is executed at a double rate to realize the fast-forwarding at double speed. Moreover, in this method, a value of time information related to decoding and reproduction that is added in data is changed to half of the value and the decode process and the reproduction process are performed according to the changed time information. Whereby, in the method disclosed in the patent document 1, the fast-forwarding of the content at the double speed is realized.
An example of another method of fast forwarding a stored content is disclosed in patent document 2. In this method, a thinning process is performed in a frame unit according to the specified fast forwarding multiplication ratio, and then the decoding is performed. In the method disclosed in the patent document 2, the thinning process is performed in a frame unit. As a result, the method disclosed in the patent document 2 realizes the fast-forwarding by realizing a skip of an image frame.    [patent document 1] Japanese Patent Application Laid-Open No. 2002-354419    [patent document 2] Japanese Patent Application Laid-Open No. 2006-295645